Iodine презентация

Properties
Under ordinary conditions iodine is solid black-grey with violet metallic luster substance. It is slightly soluble in water. Iodine is very toxic.
In heating iodine gives off violet vapors with acrid odour.

Being in nature
Due to its chemical active iodine doesn`t occur in nature in a free state.
It is rare element in spite of its little content in almost all. Iodine contains in all living organisms, water, minerals, soil. The largest quantity contains in seawater.
Lautarite is the most famous mineral of iodine.
99% of reserves are in Chile and Japan.

History
In 1811 Courtois first found iodine in ash of seaweed.
In 1813 -1814 Gay-Lussac proved than iodine is new simple substance and chemical element.